Spark initiated internal combustion gasoline engines require fuel of a minimum octane level which depends upon the design of the engine. If such an engine is operated on a gasoline which has an octane number lower than the minimum requirement for the engine, “knocking” will occur. Generally, “knocking” occurs when a fuel, especially gasoline, spontaneously and prematurely ignites or detonates in an engine prior to spark plug initiated ignition. It may be further characterized as a non-homogeneous production of free radicals that ultimately interfere with a flame wave front. Gasolines can be refined to have sufficiently high octane numbers to run today's high compression engines, but such refining is expensive and energy intensive. To increase the octane level at decreased cost, a number of metallic fuel additives have been developed which, when added to gasoline, increase its octane rating and therefore are effective in controlling engine knock. The problem with metallic anti-knock gasoline fuel additives, however, is the high toxicity of their combustion products. For example, the thermal decomposition of polyalkyl plumbates, most notably tetramethyl and tetraethyl lead, are lead and lead oxides. All of these metallic octane improvers have been banned nationwide, because their oxidation products produce metallic lead and a variety of lead oxide salts. Lead and lead oxides are potent neurotoxins and, in the gaseous form of an automotive exhaust, become neuro-active.
Further, the improvement of combustion efficiency in gasoline engines is continuously sought. Thermal efficiency of the functional operating four stroke engine developed by Nicolaus Otto (“Otto cycle engine”) is directly related to compression ratio and spark timing. The higher the compression ratio and the closer the spark timing to maximum brake torque timing, the higher the engine efficiency. Engine technology is currently limited by the availability of non-metallic octane improvers. At the refinery, significant quantities of high octane blending components are required to manufacture a high-octane fuel. In fact, limitations to the use of high concentrations of aromatics, MTBE or ETOH by regulatory mandate, increases the difficulty, the expense and the severity of refining operations to produce high octane fuels.